perf kvm: Add pointer to 'perf_kvm_stat' in kvm event

Sometimes, handling kvm events needs to base on global variables, e.g.
when read event counts we need to know the target vcpu ID; the global
variables are stored in structure perf_kvm_stat.

This patch adds add a 'perf_kvm_stat' pointer in kvm event structure,
it is to be used by later refactoring.
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230315145112.186603-2-leo.yan@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-kvm.c

@@ -209,7 +209,8 @@ static bool kvm_event_expand(struct kvm_event *event, int vcpu_id)
 	return true;
 }
 
-static struct kvm_event *kvm_alloc_init_event(struct event_key *key)
+static struct kvm_event *kvm_alloc_init_event(struct perf_kvm_stat *kvm,
+					      struct event_key *key)
 {
 	struct kvm_event *event;
 
@@ -219,6 +220,7 @@ static struct kvm_event *kvm_alloc_init_event(struct event_key *key)
 		return NULL;
 	}
 
+	event->perf_kvm = kvm;
 	event->key = *key;
 	init_stats(&event->total.stats);
 	return event;
@@ -238,7 +240,7 @@ static struct kvm_event *find_create_kvm_event(struct perf_kvm_stat *kvm,
 			return event;
 	}
 
-	event = kvm_alloc_init_event(key);
+	event = kvm_alloc_init_event(kvm, key);
 	if (!event)
 		return NULL;
 

tools/perf/util/kvm-stat.h

@@ -24,10 +24,13 @@ struct kvm_event_stats {
 	struct stats stats;
 };
 
+struct perf_kvm_stat;
+
 struct kvm_event {
 	struct list_head hash_entry;
 	struct rb_node rb;
 
+	struct perf_kvm_stat *perf_kvm;
 	struct event_key key;
 
 	struct kvm_event_stats total;
@@ -44,8 +47,6 @@ struct kvm_event_key {
 	key_cmp_fun key;
 };
 
-struct perf_kvm_stat;
-
 struct child_event_ops {
 	void (*get_key)(struct evsel *evsel,
 			struct perf_sample *sample,